class ParamInput
  def self.write(integration_params, system_mass)
    param = ""
    param_content = <<OUTPUT
)O+_06 Integration parameters  (WARNING: Do not delete this line!!)
) Lines beginning with ')' are ignored.
)---------------------------------------------------------------------
) Important integration parameters:
)---------------------------------------------------------------------
 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = %s
 start time (days)= %f
 stop time (days) = %f
 output interval (days) = %s
 timestep (days) = %f
 accuracy parameter= %s
)---------------------------------------------------------------------
) Integration options:
)---------------------------------------------------------------------
 stop integration after a close encounter = %s
 allow collisions to occur = %s
 include collisional fragmentation = %s
 express time in days or years = %s
 express time relative to integration start time = %s
 output precision = %s
 < not used at present >
 include relativity in integration= %s
 include user-defined force = %s
)---------------------------------------------------------------------
) These parameters do not need to be adjusted often:
)---------------------------------------------------------------------
 ejection distance (AU)= %d
 radius of central body (AU) = %f
 central mass (solar) = %f
 central J2 = 0
 central J4 = 0
 central J6 = 0
 < not used at present >
 < not used at present >
 Hybrid integrator changeover (Hill radii) = %f
 number of timesteps between data dumps = %d
 number of timesteps between periodic effects = %d
OUTPUT
    param << sprintf(param_content, integration_params.algorithm_type, integration_params.start_time, 
    								integration_params.end_time, integration_params.output_interval, 
    								integration_params.time_step, integration_params.accuracy,
    								integration_params.stop_after_close_encounter,
                    integration_params.allow_collisions, integration_params.collision_fragmentation,
                    integration_params.time_format, integration_params.time_relative,
                    integration_params.output_precision, integration_params.relativity,
                    integration_params.user_force, integration_params.ejection_distance,
                    integration_params.solar_radius, system_mass, integration_params.hill_radii,
                    integration_params.timesteps_between_data_dumps.to_i,
                    integration_params.timesteps_between_periodic_effects)
    return param

  end
end
